Immersive experience headset devices are now available as part of graphics display, sound, haptic and/or other sensory stimulating computing and software systems which provide a user wearing the headset device a certain sensory (visual, aural and/or touch) experience. These headset devices and/or systems also may include laser and/or infra-red detection capability, cameras, and sensors for temperature, humidity, motion, altitude, speed, and the like. These headset devices and systems come in two main varieties. The first of these main varieties of systems comprise virtual reality (V/R) systems wherein a first sub-type of V/R system often, or typically, does not actually involve much physical exertion of oneself by participating in a correspondingly real experience akin to, or correlated with, the sensory experience while using the system. Thus, with such V/R systems the user does not typically engage much in self-motivated, traveling (translational) motion, such as by running along a real sidewalk, by climbing a real mountain, by paddling a real boat, by skiing down a real ski-slope, or by cycling down a real trail or street, etc., even though the user is actually virtually experiencing any one of such activities through the user's visual, aural, and/or other sensory organs. Thus, in such systems the user is usually not part of an actual, real, traveling (translational) experience akin to the sensory experience being provided by the system—except perhaps as may be provided stationed in a vehicle with other automated or protective safety systems in place. Thus, with such V/R systems, not involving a lot of physical exertion, fogging of a vision screen of such a V/R headset has not been as much of a problem, except in cases where the user may transition, for example, from a colder environment to a warmer, more humid, environment, or where a user becomes nervous or anxious, as a result of the experience, thus increasing the heart rate and respiration of the user causing perspiration, wherein fogging of the system could negatively impact the graphics display capability of the system and the visual experience of the user in such a case.
In a second sub-type of V/R system experiences, wherein substantial physical exertion may be, or would be (as to systems still being developed), experienced, such as by swinging the arms as if using a tennis racquet or bat, or the like, while making throwing, punching or climbing motions while standing in place, while engaging in running-in-place-type motions, while using a stationary bicycle to engage in stationary cycling, or while engaging in some other active endeavor while standing or sitting in place, the user's core body temperature may actually be raised. Thus, the user's heart rate and respiratory systems may be taxed (all of course while providing for the physical safety of the user), the user's body temperature may be raised, and this would cause perspiration by the user and associated fogging of the vision screen of the V/R headset device. Such fogging, of course would interfere with the transmission of the graphics display of the device and accordingly would negatively impact the experience of the user of such a device.
As for the other type of immersive experience, there are, or will be, provided enhanced or augmented real experiences via an augmented reality (A/R) system. With such A/R systems, there are provided to the user visual, aural, and/or haptic sensory inputs while the user also actually participates in another real, correlated, experience which may involve extreme human exertion, such as by actually skiing, driving, walking, running, playing, engaging in battle, or other real experience, while simultaneously experiencing enhancing sensory inputs from the A/R system. In such, the A/R system is programmed and designed to enhance or augment the real experience in some way. Thus, such an A/R system provides graphic, sound, haptic and/or other sensory stimulating computing and software system inputs provided to the user in “layered” fashion upon the user's perceptions of the real experience, and in such a way as to not interfere with the real experience, but rather so as to enhance the user's perception, and hence ability to perform, in the real experience. Of course, while such systems involve user translational traveling and motion at times, they have nevertheless been (or would be, regarding such systems still not having been fully developed or commercialized), highly susceptible to fogging of the vision screens or lenses of such systems, and such fogging would negatively impact the experience, and even possibly create an unsafe experience.
There is lacking in the prior art a wearable virtual reality (V/R) or augmented reality (A/R) system adapted for heating, either using an on-board battery, or provided with external power, to prevent fogging of the headset display, wherein a heating element on the lens or viewing screen is connected with an on-board battery or other power source for the system. This is because early systems were primarily V/R systems for stationary use where the user would not expend a lot of energy causing perspiration and excess condensation of such within the V/R headset enclosure. But with the advent of more active gaming and other A/R systems, in addition to such V/R systems, the presentation of fogging conditions is becoming more common.
Thus, virtual reality, enhanced reality, and augmented reality system users, for example V/R or A/R headset users, would in certain instances find it desirable to use virtual reality, enhanced reality and augmented reality systems while engaging in activities which would involve conditions contributing to condensation build-up on a viewing screen or lens of the system, where even momentary impairment of vision by fogging would negatively impact the anticipated experience and would otherwise be problematic and could even be dangerous. When the temperature of such a viewing screen or lens has dropped, or would drop, below a dew-point temperature, i.e., the atmospheric temperature below which water droplets would condense and dew would form, fogging has occurred, or would occur, on the viewing screen or lens.
Thus, for example, an A/R system user would experience fogging of an A/R headset lens, through which they could see variable terrain, as they would be engaged in skiing down a mountain assisted by GPS-oriented map information on a heads-up display portion of the lens. As users would work hard to accomplish the task of skiing down the mountain, their eyes and faces around their eyes would perspire, and combined with other moisture in the air, such would cause that the lens, having been made colder to below a dew point by the exterior environment, would become fogged with condensation on the lens, which would obstruct the user's vision causing a less enjoyable or even unsafe condition.
A common characteristic of such wearable portable lenses or viewing screens is that they would be lightweight enough to be worn on a user's head, and they would be positioned relatively closely to a user's face such that the user's breath and body heat would exacerbate fogging conditions. Examples of fog-prone V/R and A/R systems intended for use during various activities would include a V/R headset for holding a hand-held portable electronic visual display device, such as a smart phone device, up to the user's eyes, or alternatively custom end-user V/R or A/R headsets. While the V/R headsets tend to involve more of an immersive experience with sometimes less physical exertion, A/R headsets may be used while engaging in physical exertion, such as active gaming activities, paintball games, tactical and battlefield related activities, athletic activities, such as downhill skiing, cross-country skiing, snowboarding, snowmobiling, sledding, tubing, ice climbing, rock climbing, hiking, mountaineering, and the like, or for use while engaging in other duties or activities requiring the user to be outside in snowy or other inclement weather conditions conducive to fogging.
Examples of other fog-prone A/R guidance systems would include transparent medical face shields worn to prevent pathogens from getting into the user's mouth or eyes, a transparent face shield portion of a motorcycle or snow-mobile helmet, and eye glasses for use while cycling or playing games. Thus, fogging that impairs vision is a common problem where vision screens or lenses form, or partially form, an enclosure around a user's eyes, especially when such devices are used in colder, or otherwise inclement, weather conditions. To the extent such A/R or V/R systems are truly and completely portable, they would be powered by batteries either on a frame for the system, or carried on the user's person with a wired interconnection between the battery and the system. Other such systems may only be partially portable, perhaps tethered to a computerized V/R system, such as for example a PC gaming system.
There is not known the usage of any active technology to prevent fogging of headset-type A/R or V/R displays, portable or otherwise, in part generally because the problem has not been largely foreseen; such displays are still relatively new commercially speaking, or in some A/R applications still nonexistent, in the marketplace. There have been various active apparatus, including fans and conductive apparatus, devised for use with standard goggles to prevent fogging of the same, but such goggles are quite different than a standard V/R or A/R headset. For one, such goggles are typically designed with venting so as to combat fogging employing airflow readily available and somewhat effective because of fast traveling motion of a user associated with many of the various activities for which such goggles often have been used—i.e., for snowboarding or skiing. Such rapid traveling motion serves to force fresh air into the goggle cavity, which has helped to keep fog at bay. However, such rapid traveling motion is not typical with many, if not most, V/R systems, whereas portable A/R headset systems may involve fast traveling motion, such as skiing or cycling, but the A/R headset systems are still largely being developed for mass commercial use.
With heated-lens goggles, there have been used a layer of polyethylene terephthalate (PET) having a very thin indium-tin-oxide layer, silver nanowires, or other thin-film heater affixed thereto, together with a silver ink or other bus bar of a suitable consistency and thickness applied over the edge of the resistive element heater, so as to make sufficient consistent electrical contact with the resistive element heater, and so as to also provide a thick and substantial enough bus bar element to be able to make a substantial electrical contact through the bus bar.
Thus, as shown in FIG. 1, there have been various conductive apparatus devised for preventing condensation build-up on non-A/R or non-V/R goggle inner lenses, comprising a known device, comprising a rivet 10 and contact 112 for interconnecting such a device's battery with a bus bar 116 painted onto a resistive-element heater (such as for example an Indium-Tin Oxide thin film heating element or a carbon-nano-wire heating element) 108 with a known contact system 100 on a goggle eye-shield lens 102 having comprised a polycarbonate substrate 104 as illustrated in FIG. 1. Thus, the goggle eye-shield lens 102 has comprised a layer of polyethylene terephthalate (PET) 106 having indium-tin-oxide, silver nanowires, or other thin-film heater 108 affixed thereto by a known method of deposition, and having a silver ink bus bar 116 of a suitable consistency and thickness painted over the edge of the resistive element heater 108, so as to make sufficient consistent electrical contact with the resistive element heater, and so as to also provide the thick and substantial enough bus bar element 116 to be able to make contact by putting rivet 110 through the bus bar, the metal contact element 112 in contact with the silver ink bus bar, the resistive element heater 106, and the eye-shield substrate 104. Layering these materials onto a thin goggle eye-shield lens 102 has created a lightweight, transparent eye-shield 102 that has warmed when current has passed through the thin-film heater 108. Passing electrical current through the lead wire 114 to the contact 112 and silver ink bus bar 116 has in turn passed a current through the thin-film heater 108, warming the surface of the lens. The goggle eye-shield substrate 104 may be seen in this instance as providing rigidity so as to enable a sufficiently sturdy and durable connection between a battery (not shown) and the eye-shield heating element 108 through the silver ink bus bar 116 and the metal contact 112.
However, the above-described system, wherein the silver ink needs to be applied over the ITO in a consistent manner so as to make an effective and uniform electrical connection across the length of the goggle eye-shield, has been an inefficient method to make an electrical interconnection system for an eye-shield, and has been more difficult and expensive to implement because it has required additional steps, and thus additional labor and cost, to perform.
Additionally, inserting the rivet 110 through the edge of the layered lens 102 would weaken the integrity of the substrate 104 and silver ink bus bar 116, either of which could crack upon flexion around the rivet hole in the substrate. Further, a silver ink bus bar 116 would be painted on and would not create a strong enough connection point for a lead wire 114 to connect, thus this method would require the use of the contact 112 and rivet 110 to connect the lead wire 114 to the silver ink bus bar 116. Since inserting the rivet 110 would require putting a hole in the substrate 104 and the silver ink bus bar 116, would weaken the integrity of the substrate, this method would introduce cracks, or breakage, of the substrate upon flexion at or around the hole required by the rivet.
Again, there is a lacking in the prior art for an interconnection system to interconnect the battery of a goggle eye-shield, as well as an A/R or V/R headset lens or vision screen, with the resistive-element heater on the lens of such provided in a way so as to be easy to manufacture, involving fewer manually performed steps, so as to be more cost-effective to manufacture, which would provide an optimal electrical interconnection between the heating element and the battery, and which would be readily adaptable for allowing customized tuning of heating of an irregularly-shaped eye-shield, viewing screen or lens substrate, to allow even heating or customized pattern heating of the same.
A perfectly rectangular substrate 200, as shown in FIG. 2, would be less susceptible to hot spots because the current from the battery 214 flows evenly through the ITO 202 between and through the upper and lower bus bars 210, 212. Most A/R and V/R viewing screens, or lenses, however, are of irregular shape (other than square or rectangular), for example being rounded or having a cut-out portion corresponding to resting upon the bridge of a user's nose, so such would be subject to problems of hot spots and also would not provide for easily customizable heating of the viewing screen or lens to allow even heating of the same. Similarly as would be the case with A/R and V/R viewing screens or lenses, goggle eye-shields, such as the eye-shield 500 shown in FIG. 5, have been subject to hot spots in the ITO 502 at a location 522 positioned directly over the cut-out 507 of the eye-shield adapted for sitting upon the bridge of the user's nose; a similarly shaped viewing screen of an A/R or V/R system would likewise be subject to such hot spots, though again there have been no heated A/R or V/R system headset viewing screens or lenses.
The reason for hot spots on irregularly-shaped A/R or V/R vision screen or lens substrates would be because the electrical resistivity between the electrical connections across the resistive elements on each substrate would be greater or lesser at different locations on the substrate such that the amount of electrical current consumed in the areas with less distance between terminal connections would be greater, and the amount of electrical current consumed in areas with greater distance between the terminal connections would be less. Thus, as shown on a theoretical vision screen or lens substrate 500 of FIG. 5, where there would be a bus bar 506 across the top of the brow of the substrate, and a corresponding bus bar 508 across the eye-well portion of the substrate 500 and over the bridge of the cut-out 507 of the eye-shield substrate adapted for resting on the bridge of a user's nose, the distance between the bus bars at locations 513, 515, positioned directly over the user's eyes, would tend to be cooler than the position 517, or area B, positioned directly above the cut-out portion of the eye-shield substrate adapted for resting on the bridge of the user's nose. Again, this is because more current would be used (and wasted) over the bridge of the nose than would be used directly over the eyes, and for similar reasons uneven heating would occur in a similarly designed A/R or V/R irregularly-shaped vision screen substrate or lens substrate.
To overcome fogging conditions, enough power would need to be applied to overcome the fog in the areas with the greatest distance between the terminal connection points, and applying the same amount of power over the smaller areas would cause the smaller areas to overheat, which in turn would waste power (assuming a portable, battery-powered system having more limited power supplies). Because of the irregular shape of A/R and V/R vision screen and lens substrates, these problems would exist whether one is considering resistive-wire applications or resistive-film applications for heating. Thus, the problem would result in limited usefulness of heating of V/R and A/R headset vision screens and lenses.
In one type of V/R and A/R headset, the inner lens or viewing screen comprises separate, dual, substantially-circular inner lenses communicating visually with a split-screen display within the headset system (e.g., as accomplished with a smart phone or other display system attached to or otherwise within the system) such that electronics in the system are used to simulate a 3-D environment visual presentation to the user, as is known in the art. The dual circular inner lenses of such systems would thus be susceptible to fogging, and because of the enclosed nature of the headset, and the fact that in some, if not many, A/R applications there is not a lot of high-speed, translational, traveling movement by the user, but rather active engagement by a user standing, dancing, jumping, or running in place, such that venting of the system, even if venting of such systems had been taught, which it hasn't, would not be all that helpful in reducing fogging, because such would require substantial airflow across the viewing screen or lens. Thus, there needs to be determined a need for active technology for preventing fogging of the inner lenses or vision screens of current V/R and A/R systems.
In another type of A/R or V/R system, there is provided an inner viewing screen, or lens, that is more in the shape of a typical goggle system, wherein there is employed a single inner lens comprising an arched portion over the brow of a user's eyes, and further comprising a cut-out portion corresponding to a portion of the frame of the goggle that rests on the bridge of the user's nose, all similar to the theoretical vision screen shown in FIG. 5.
Standard anti-fogging systems found in prior art goggles, such as are found in U.S. Pat. No. 9,301,879 to McCulloch et al., for Goggle With Easily Interchangeable Lens That Is Adaptable For Heating To Prevent Fogging, would not be ideal alone for either type of A/R or V/R system (dual substantially circular, or having a cutout for the bridge of the user's nose), since as taught in the '879 McCulloch et al. patent, there is provided for the use of a battery-powered resistive heating element (such as ITO, carbon nano-wire, or other heating element technology) deposited on a single goggle lens, and not the ready application of such heating elements for a pair of substantially circular lenses as part of such a split-screen presentation system common to some types of standard A/R and V/R headset systems. Further, the McCulloch et al. system alone may be susceptible to hot spots in the lens directly over the bridge of the nose of a user.
And though U.S. Pat. No. 8,566,962, for PWM Heating System for Eye Shield, to Cornelius, and U.S. Pat. No. 9,210,737, for Multiregion Heated Eye Shield, to Cornelius, teaches a multi-channel, multi-region heated eye shield using PWM, as taught in PCT Patent Application, Serial No. PCT/2016/058330, for Electrical Interconnection System For Customized Heating of an Eye-Shield, to O'Malley et al., it would have been somewhat difficult and more expensive to electrically interconnect and efficiently apply heating elements to circular lenses of a vision screen, such as the aforementioned types of standard A/R or V/R vision screen systems, since not only are the lenses of such systems irregular, being non-rectangular in shape, so as to not as easily permit even heating of the same, but also such lenses are typically smaller than would easily accommodate such a prior art heating element and bus bar application as taught in the aforementioned patents to McCulloch et al., and Cornelius. This, in turn, would make the application of bus bars somewhat more difficult, time-consuming, and therefore less cost-effective to implement for this type of an A/R or V/R system. Further, without tuning of application of heating to such rounded lenses and irregularly-shaped substrates, the heated lenses of such would be susceptible to hot spots, because the electrical resistivity between the electrical connections across the resistive elements on the lenses would be greater or lesser at different locations on the lenses, such that the amount of electrical current consumed in the areas with less distance between terminal connections is greater and the amount of electrical current consumed in areas with greater distance between the terminal connections is less.
Thus, regardless of whether a lens system comprises a dual, substantially circular pair of lenses, or a singular irregularly-shaped lens with a cutout for the user's nose, in order to overcome fogging conditions, enough power would need to be applied to overcome the fog in the areas with the greatest distance between the terminal connection points, causing the smaller areas to overheat, which in turn would waste power. And this problem would be exacerbated in some portable V/R or A/R systems where venting has not been employed, thus enhancing the need for active defogging technology in such systems. Thus, the problem described above relating to more efficiently interconnecting heating elements of such systems with a power source, would result in a limited usefulness of attempting to apply heating to prevent fogging of such system viewing screens.
Other examples of disclosures providing for heating of eyewear lenses include the following: U.S. Pat. No. 4,868,929, to Curcio, for Electrically Heated Ski Goggles, and U.S. Pat. No. 7,648,234, to Welchel et al., for Eyewear with Heating Elements, each comprising an eye-shield with embedded resistive wires operatively connected via a switching device to a power source pack adapted to produce heating of the eye-shield for anti-fog purposes. Neither the Curcio nor Welchel disclosures teach of a bus bar contacting a transparent heating element, such as may be made of Indium-Tin-Oxide (ITO), carbon-nano-wires, or other known heating element material, but rather they teach of interconnection of circuit wires to resistive wires embedded in the lens. Nor do Curcio nor Welchel teach an easier-to-manufacture bus bar interconnection system to achieve customized heating of an irregularly-shaped lens or viewing screen of an A/R or V/R system.
US Patent Application No. 2009/0151057A1 to Lebel et al., for Reversible Strap-Mounting Clips for Goggles discloses use of thin-film heating elements used for heating a goggle eye-shield with a push-button switch for turning on power from a battery carried on an eyewear band or eyewear arm. While Lebel et al. teaches of a transparent, thin-filmed heating element, it does not teach about how the bus bar is connected to the heating element. Nor does Lebel teach an easier-to-manufacture bus bar interconnection system to achieve customized heating of an irregularly-shaped V/R or A/R lens or vision screen. Thus, Lebel would be susceptible to a hot spot over the arched cut-out in the goggle eye-shield of that patent, as described above, where it is adapted to accommodate a user's nose, and using such a device in a limited battery-powered application would unduly discharge the battery and diminish the amount of time a battery would last during a particular use.
U.S. Pat. No. 5,351,339 to Reuber et al., for Double Lens Electric Shield, recognizes the problem of un-even heating where an electroconductive film is deposited on an irregular-shaped visor lens, and it proposes a specific bus bar configuration (electrodes 50 and 60) that addresses the problem of making the distance between electrodes substantially the same for fairly uniform flow of electrical current across the electroconductive film. However, the eye-shield of Reuber is more uniform than that of a typical A/R or V/R headset system lens. Accordingly, the configuration of the electrode bus bars of Reuber would not suffice for the viewing lenses configuration of a typical A/R or V/R headset system. Further, the bus bar of Reuber is connected with a rivet to a larger eye-shield itself, and while this may be somewhat suitable for a visor for a motorcycle helmet, as with Reuber, such attachments to an A/R or V/R headset system would be ineffective in part because of the issue of the additional number of steps and additional cost necessary for manufacture, and in part because of the size of the lenses of an A/R or V/R system may be too small to effectively accommodate such a rivet. Rueber does not teach the use of a physically altered configuration of bus bar having protruding, recessed, or otherwise physically altered portions of a bus bar, which would create partial contact surface areas of the bus bar. Thus, Rueber does not teach a customized heating pattern applicable to a heating element on a substrate, together with a less-costly-to-manufacture clamping, or other mechanized or other engaging, system for holding portions of a bus bar against a thin-film heating element, all while allowing other portions of the bus bar to be out of contact with the heating element, in order to apply a specific heating pattern to a V/R or A/R system to prevent hot spots or to otherwise provide customized heating.
Thus, a problem with prior art heated goggle lenses which have employed electrical heating of the lenses is that of uneven heating over the entire surface of an irregular-shaped lens. Thus, such a problem would also obtain if applied to A/R and V/R system lenses which are manufactured with an irregular shape required to maintain a position close to the face of the wearer. Various general attempts to evenly heat an eye-shield across its entire surface have been made with serpentine wires, or strips of thin-film heating material, included on, or within, eye-shield lenses, as for example in published US Patent Application No. 2008/0290081A1 to Biddell for Anti-Fogging Device and Anti-Fogging Viewing Member, U.S. Pat. No. 4,638,728 to Elenewski for Visor Defroster, and US Published Patent Application No. 2013/0043233A1, to Elser et al., for Device for Active Heating of Transparent Materials.
These references do not teach use of a bus bar interconnection system applied to a wearable, portable V/R or A/R headset viewing screen or lens, let alone teaching such an interconnection system having a physically-altered configuration bus bar allowing partial contact of the bus bar with a transparent heating element for supporting even heating of an irregular-shaped A/R or V/R lens or vision screen, or supporting customized heating of such a lens or vision screen, with a transparent film (such as ITO), carbon-nano-wire, or other heater affixed, or otherwise attached to cover a lens surface. Further these references do not teach such a system combined together with a less-costly-to-manufacture clamping, or other mechanized or other engaging, system for holding portions of the bus bar against the heating element while allowing other portions of the bus bar to be out of contact with the heating element, for applying a specific heating pattern to the lens, to prevent hot spots, or to otherwise provide customized heating, and such has not been taught in the prior art.
U.S. Pat. No. 5,471,036 to Sperbeck for Goggle Defogging System with Transparent Indium-Tin-Oxide Heating Layer Disposed on a Lens provides recognition of the problem of uneven heating of a thin-filmed heating element on a lens over the bridge of a user's nose, and other areas, and provides that “the ITO coating includes an interior heating zone (33) that is electrically isolated form the edge of the inside layer.” Further, Sperbeck provides, “the region (48) where the bus bars cross the nose area (41) of the goggle lens is isolated from the interior heating zone (33).” Sperbeck further provides: “As a result, the bus bar only contacts the interior heating zone along the top of the goggle lens and along the bottom of the eye regions (37) of the goggle lens located on either side of the nose area (41).” However, Sperbeck does not teach use of a bus bar interconnection system for use with a V/R or A/R headset system, let alone such an interconnection system having a physically-altered configuration bus bar (as by crimping, bending, serpentining or the like) specifically for the purpose of allowing partial contact of the bus bar with a transparent heating element for supporting even heating of an irregular-shaped eye-shield, or customized heating of such an eye-shield, with a transparent film (such as ITO), or carbon-nano-wire, heater affixed, or otherwise attached, to cover a lens surface. Further, Sperbeck doesn't add a clamping, or other mechanized or other engaging, system to attach portions of such a physically-diverted heating element, enabling specific pattern heating by applying a specific heating pattern to the eye-shield to prevent hot spots, or to otherwise provide customized heating, all in a system that is less costly to manufacture overall than prior-art systems.
In contrast, the bus bars of Sperbeck, make a uniform, smooth-transition path across the path of the lens, and they are not taught to be used in conjunction with a clamping, or other engaging peripheral member for holding only diverted portions of the bus bar against the ITO. Rather, Sperbeck teaches that “The interior heating zone of the ITO coating can be electrically isolated by scoring a groove around the periphery of the ITO coating. Alternatively, acid etching can be used to remove a peripheral part of the ITO coating.” Still further, Sperbeck makes use of a prior art, silver ink priming, method of making contact between the ITO coating and the bus bars, stating: “Multiple layers of silver are primed atop the ITO coating . . . .” Sperbeck makes use of a tab 43 and connector 46 for interconnecting the bus bar, leads from the battery, and the ITO on the eye-shield substrate.
In U.S. Pat. No. 9,210,737, for Multiregion Heated Eye Shield, to Cornelius, there is provided an anti-fog eye-shield having an apportioned thin resistive-film heater on the eye-shield to enable even heating of the lens, or other custom heating of the lens, for use in an anti-fog goggle, an anti-fog dive mask or other portable transparent anti-fog eye-protecting shield. In that patent, there is taught apportioning of the heater on the eye-shield with either a split bus bar for each apportioned heating area, or a single bus bar for multiple apportioned heating areas. However, as described above, an altered configuration bus bar presenting partial connection surface areas according to protruding, or otherwise extended, contact areas, is not taught in that patent to Cornelius. Nor is such a system taught in the Cornelius patent combined together with a less-costly-to-manufacture clamping, or other engaging, system for holding portions of the bus bar against the heating element, all while allowing other portions of the bus bar to be out of contact with the heating element. Such a system would be beneficial and cost effective for applying a specific heating pattern to smaller rounded lenses or other irregular viewing screens of newer A/R and V/R system lenses and viewing screens in order to prevent hot spots, or to otherwise provide customized heating, for such systems.
Referring to FIGS. 2-4, a series of general schematic representations of current flow paths is provided and described as background for further description and understanding of the invention and its operation. Referring now specifically to FIG. 2, there is shown a schematic representation of current 204 flowing through a rectangular eye-shield 200 having a thin film-heater 208 attached to a layered lens 202 with an upper bus bar 210 affixed to the entire upper length of the layered lens 202, and a lower bus bar 212 affixed to the entire lower length of the layered lens 202. A battery power source 214 with positive terminal 216 and negative terminal 218 connects to the upper bus bar 210 and lower bus bar 212, using a rivet 224, through a positive circuit wire 220 and a negative circuit wire 222.
If the bus bars 210, 212 are uniformly distributed along the entire upper peripheral length and lower peripheral length of the layered lens 202, and a thin-film heater 208 is also uniformly applied to the surface of the layered lens 202, current 204 will flow uniformly through the thin-film heater 208 to evenly heat the layered lens 202. With a perfect application of the thin-film heater 208 and bus bars 210, 212, the surface of the layered lens will avoid hot spots. However, uniform application is difficult and expensive to achieve. Additionally, a perfectly rectangular eye-shield 200 is impractical because the human face is not flat and rectangular, but is instead curved and intricate.
Referring to FIG. 3, there is shown another schematic representation of current 304, 306 flowing through a transparent thin-film heater 308 of a rectangular eye-shield 300 having a layered lens 302. There is further shown an upper bus bar 310 affixed to a portion less than the entire upper length of the layered lens 302 with gaps or cutouts on both sides of the upper layered lens 302, and a lower bus bar 312 affixed to a portion less than the entire lower length of the layered lens 302 located directly opposite of the upper bus bar 310, with gaps or cutouts on both sides of the lower bus bar 312. A battery power source 314 with positive terminal 316 and negative terminal 318 connects to the upper bus bar 310 and lower bus bar 312 through a positive circuit wire 320 and a negative circuit wire 322.
Because upper bus bar 310 and lower bus bar 312 do not occupy the entire upper and lower lengths of the layered lens 302, currents 304, 306 do not uniformly flow across the layered lens 302. Instead of flowing uniformly across layered lens 302, current 306 bows out into areas of less direct paths creating heating that is not uniform. A warm spot forms in the middle of layered lens 302 where current 304 flows directly, in the shortest path, between upper bus bar 310 and lower bus bar 312. Alternatively, less warm spots form around the outer periphery areas of the eye-shield 300 where current 306 bows out into areas of less direct paths, creating uneven heating. Such uneven heating is undesirable in an eye-shield when dissipating fog or condensation because while the warm spot dissipates fog, the less warm spots might not dissipate fog, leaving a user or wearer of the eye-shield 300 with partially restricted vision. Alternatively, if enough power and current is supplied to the eye-shield 300 in order to dissipate all fog across the entire surface of the eye-shield 300, a hot spot will form where current 304 flows directly between bus bars 310, 312, using unnecessary and excessive amounts of power from battery 314, and lessening the total time a user or wearer can use eye-shield 300.
Referring to FIG. 4, there is shown a schematic representation of current 404, 406 flowing through a transparent thin-film heater 408 of a rectangular eye-shield 400. The rectangular eye-shield 400 comprises a transparent thin-film heater 408 attached to a layered lens 402 with two upper bus bars 410a, 410b spaced apart and affixed to a portion less than the entire peripheral upper length of the layered lens 402 with a gap 412 separating the two upper bus bars 410a, 410b, and a lower bus bar 414 affixed to a portion less than the entire peripheral lower length of the layered lens 402, with gaps or cutouts on both sides of the lower bus bar 414, positioned such that the lower bus bar 414 is offset laterally and directly across from the gap 412 separating the two upper bus bars 410a, 410b. A battery power source 416 with positive terminal 418 and negative terminal 420 connects to the upper bus bars 410a, 410b and lower bus bar 414 through a positive circuit wire 422 and a negative circuit wire 424, supplying power to upper bus bars 410a, 410b, lower bus bar 414, and the transparent thin-film heater 408.
Because upper bus bars 410a, 410b and lower bus bar 414 do not occupy the entire upper and lower lengths of the layered lens 402, and a gap 412 separates bus bars 410a and 410b, currents 404, 406 do not uniformly flow across the layered lens 402. Instead of flowing uniformly across layered lens 402, currents 404, 406 are skewed, flowing diagonally across layered lens 402 from upper bus bars 410a, 410b to lower bus bar 414. Current will mostly flow in straight, direct paths with a higher concentration flowing over the shortest path, however additional current will bow out into areas of less direct paths creating heating that is not uniform. Warm spots form on layered lens 402 where currents 404, 406 flows directly, in the shortest paths, between upper bus bars 410a, 410b and lower bus bar 414. Alternatively, less warm spots form around the outer periphery areas of the eye-shield 300, and near gap 412, where currents 404, 406 bow out into areas of less direct paths, or where the distance traveled by the currents 404, 406 is longer, creating uneven heating. Such uneven heating in this manner is also undesirable in an eye-shield when dissipating fog or condensation, because while the warm spots dissipate fog, the less warm spots might not dissipate fog, leaving a user or wearer of the eye-shield 400 with restricted vision. Alternatively, if enough power and current is supplied to the eye-shield 400 in order to dissipate all fog across the entire surface of the eye-shield 400, hot spots will form where currents 404, 406 flow directly between upper bus bars 410a, 410b and lower bus bar 412, using unnecessary and excessive amounts of power from battery 414, lessening the total time a user or wearer can use the eye-shield 400.
While the above descriptions of current flow through a transparent heating element may have consequences resulting in wasted power and uneven heating if misapplied or misunderstood, intentional use of patterned heating from a bus bar may be advantageously used to tune heating to be more efficient and customized as further described herein.
Referring to FIG. 5, there is shown a graphical representation front view of a prior, irregular-shaped eye-shield 500 comprising a thin-film heater 504 attached to a layered lens 502, an upper bus bar 506 attached to the peripheral upper length of the layered lens 502, and a lower bus bar 508 attached to the peripheral lower length of the layered lens 502. A battery power source 510 with a positive terminal 512 and negative terminal 514 connects to the upper bus bar 506 and lower bus bar 508 through a positive circuit wire 516 and a negative circuit wire 518 attached to the upper bus bar 506 and lower bus bar 508 using rivets 520, supplying power to upper bus bar 506, lower bus bar 508, and the thin-film heater 504.
An irregular shape of an eye-shield 500 is necessary in order to fit the unique curvature and shape of a user's face. However, because of the irregular shape of eye-shield 500, current supplied by the battery power source 510 will not uniformly flow across the layered lens 502. Instead of flowing uniformly across layered lens 502, current will try to flow from upper bus bar 506 to lower bus bar 508 through thin-film heater 504 in the shortest, most direct path. Because of the irregular shape of layered lens 502, the shortest, most direct path occurs in region B 522 above the nose cut-out portion of eye-shield 500, resulting in a warm/hot spot in region B 522 above the nose cut-out portion of the eye-shield. Alternatively, less warm spots form around the outer periphery areas of the eye-shield 500 in regions A and C 524, 526, respectively, where current flows in a longer, or less direct, path from upper bus bar 506 to lower bus bar 508, creating uneven heating of eye-shield 500.
Such uneven heating is undesirable when dissipating fog or condensation, because while the warmth in region B 522 dissipates fog, the less warm spots in regions A and C 524 526 might not dissipate fog, leaving a user or wearer of the eye-shield 500 with partially restricted vision through regions A and C 524, 526, respectively. Alternatively, if enough power and current is supplied to the eye-shield 500 in order to dissipate all fog across the entire surface of the eye-shield 500 in regions A, B and C 524, 522, 526, respectively, a hot spot will form above the nose cut-out of eye-shield 500 where current flows in the shortest, most direct path between upper bus bar 506 and lower bus bar 508. In this way, unnecessary and excessive amounts of power from battery 510 are used, lessening the total time a user or wearer can use eye-shield 500 to dissipate fog.
Referring to FIG. 6, there is shown a graphical representation front view of a prior, split-bus-bar, irregular-shaped eye-shield 600 comprising a thin-film heater 604 attached to a layered lens 602, an upper bus bar 606, made by painting silver ink onto the layered lens 602, attached to the peripheral upper length of the layered lens 602, and two lower, split, bus bars 608a, 608b, also made by painting silver ink onto the layered lens 602, attached to the peripheral lower length of the layered lens 602 and spaced such that there is a gap between them situated at a nose cut-out portion of eye-shield 600. A battery power source 610 with a positive terminal 612 and negative terminal 614 connects to the upper bus bar 606 and lower bus bars 608a, 608b through a positive circuit wire 616 and a split negative circuit wire 618 attached to the upper bus bar 606 and lower bus bars 608a, 608b, using rivets 620, supplying power to upper bus bar 606 and the lower bus bars 608a, 608b. 
The irregular shape of eye-shield 600 is necessary in order to fit the unique curvature and shape of a user's face. Similarly to that described above in connection with FIG. 5, without the region between bus bars 608a, 608b, current supplied by the battery power source 610 would not uniformly flow across the layered lens 602. Instead of flowing uniformly across layered lens 602, current would flow more in the center of the lens where the path is the shortest and most direct, thus causing a hot spot in the center of the layered lens 602.
However, the configuration of bus bars 606, 608a, 608b on the eye-shield, where a silver ink upper bus bar 606 is painted along the entire upper periphery edge of layered lens 602, and where two lower bus bars 608a, 608b are painted along the lower periphery edge of the layered lens, such that there is a gap at the nose cut-out portion of eye-shield 600, creating a more uniform and customized heating of the eye-shield 600 than did previously described eye-shield 500. Eye-shield 600 does not, however, create an ideal situation to uniformly heat layered lens 602 while still conserving power since the bus bars are painted on in a time-consuming, expensive process, and further, eye-shield 600 may be more bulky and cumbersome, needing multiple bus bars and circuit wires to function properly.
Referring to FIG. 7, there is shown a graphical representation front view of a prior, irregular-shaped eye-shield 700 comprising a thin-film heater 704 attached to a layered lens 702. An upper bus bar 706 is attached to the peripheral upper length of the layered lens 702, and a lower bus bar 708 is attached to the peripheral lower length of the layered lens 702. The eye-shield 700 overcomes a limitation of the split bus bar system of eye-shield 600 by providing a slit 703 between lower bus bar 708 and the thin-film heater 704, such that there is no contact between the lower bus bar 708 and the thin-film heater 704 on the layered lens 702 at a location just above the cutout portion of the eye-shield adapted for resting above the bridge of a user's nose. The slit 703 is typically formed by etching, or otherwise cutting, the transparent heating material away from the location of the lens where the bus bar has been applied. A battery power source 710 with a positive terminal 712 and negative terminal 714 connects via the positive terminal to the upper bus bar 706 through a positive circuit wire 716, and connects via the negative terminal to the lower bus bar 708 through a negative circuit wire 718. The upper bus bar 706 and lower bus bar 708 are further attached or connected to the heating element 704 and lens substrate 702 using rivets 720 for supplying power to the upper bus bar 706 and the lower bus bar 708.
As described previously for eye-shield 600, the irregular shape of eye-shield 700 is necessary in order to fit the unique curvature and shape of a user's face. However, because of the irregular shape of eye-shield 700, current supplied by a battery power source 710 would not uniformly flow across the layered lens 702. However, this configuration of bus bars on an eye-shield, similar to that of eye-shield 600, where upper bus bar 706 is along the entire upper periphery edge of layered lens 702, and lower bus bar 708 is situated such that there are two contact areas of bus bar 708 with thin-film heater 708 separated by a slit at the nose cut-out portion of the eye-shield 700, has created a more uniform and customized heating of the eye-shield 700 than did previously described eye-shield 500, and similarly has heated as did eye-shield 600. Like eye-shield 600, however, eye-shield 700 has not created an ideal situation to provide customized, efficient, uniformly applied heat to layered lens 702 while still conserving power.
Referring to FIG. 8A, there is shown a graphical representation front view of a smaller, conceptual circular eye-shield 800, with slitting at 805 similar to that shown and described in connection with FIG. 7, but instead as might be applied to the inner lenses of an A/R or V/R system. Conceptual eye-shield 800 comprises a thin-film heater 804 attached to a layered lens 802, an upper painted silver ink bus bar 806 attached to the peripheral upper length of the layered lens 802, and a lower painted silver ink bus bar 808 attached to the peripheral lower length of the layered lens 802. Presumably, the battery power source 810 with a positive terminal 812, and a negative terminal 814, would connect to the bus bars via a positive circuit wire 816 to the upper bus bar 806, and via a negative circuit wire 818 to the lower bus bar 808 using rivets 820, however it can be seen that the use of such a connection method would be problematic with attempting to place a rivet, which would comprise design and implementation issues on such a smaller substrate surface. Thus, presumably, conceptually, power would be supplied through circuit wires 816, 818 to the upper bus bar and the lower bus bar.
Such a small, circular eye-shield 800 would be desirable where a user desires to achieve a sleek, aerodynamic profile while still protecting their eyes. But because of the small circular shape, current supplied by a battery power source 810 would not uniformly flow across the layered lens 802, but more power would instead flow from upper bus bar 806 to lower bus bar 808 through a thin-film heater 804 in the shortest, most direct path on the outer perimeter of the layered lens where the bus bars are shown closest together. Alternatively, a less warm spot would form in the center of the layered lens 802 where the distance between upper bus bar 806 and lower bus bar 808 would be greatest, which would create uneven heating of the eye-shield 800. Such uneven heating would be undesirable in an eye-shield when dissipating fog or condensation because while the warm regions around the perimeter of the layered lens 802 dissipates fog, the less warm spots in the center region of the layered lens 802 might not dissipate fog, leaving a user with partially restricted vision. Alternatively, if enough power and current is supplied to the eye-shield 800 in order to dissipate all potential fog across the entire surface of the eye-shield 800, hot spots would form in the regions around the perimeter of the layered lens 802 where current flows in the shortest, most direct path between upper bus bar 806 and lower bus bar 808, which would use unnecessary and excessive amounts of power from battery 810, would cause hot spots on the les 802, and would waste power, thus lessening the total time a user or wearer could use the eye-shield 800 to dissipate fog. The implementation of slits 805 as shown is intended to resolve some of the aforementioned uneven heating problem, but overall is not considered an entirely adequate solution for reasons similar to those described in connection with FIG. 7.
Referring to FIG. 8B, there is shown an alternative conceptual embodiment of a graphical representation of a smaller circular eye-shield 850, comprising a thin-film heater 854 attached to a layered lens 852. Layered lens 852 would have painted thereon three silver ink upper bus bars 856a, 856b, 856c attached to the peripheral upper length of the layered lens 852 with gaps separating each of the upper bus bars in split-bus-bar fashion. Layered lens 852 also would have painted thereon three lower bus bars 858a, 858b, 858c attached to the peripheral lower length of the layered lens with gaps separating each of the lower bus bars in split-bus-bar fashion. A battery power source 860 with a positive terminal 862 and negative terminal 864 would connect via a split positive circuit wire 866 to the three upper bus bars 856a, 856b, 856c, and the power source would connect via a split negative circuit wire 868 to the three lower bus bars 858a, 858b, 858c. Attachment of the circuit wires and the bus bars would presumably be through rivets, however it can be readily seen that such would present design and connection problems for so many rivets required on such a small substrate surface.
Just as described previously for eye-shield 800, a small, circular eye-shield 850 is desirable in cases where a user desires to achieve a sleek, aerodynamic profile while still protecting their eyes. Because of the small circular shape, a common current supplied by a single battery power source 860 would not uniformly flow across the layered lens 852, but would instead flow from the upper bus bars 856a, 856b, 856c to lower bus bar 858a, 858b, 858c through a thin-film heater 854 in the shortest, most direct path. Similar to eye-shield 800, in the circular eye-shield 850, the shortest, most direct path would occur near the outer perimeter of the layered lens 852. Alternatively, with a common current power source, a less warm spot would form in the center of the layered lens 852, where the distance between upper bus bars 856b and lower bus bars 858b would be greatest, creating uneven heating of the eye-shield 850. Such uneven heating is undesirable in an eye-shield when dissipating fog or condensation because while the warm regions near the perimeter of the layered lens 852 dissipates fog, the less warm spots in the center region of the layered lens 852 might not dissipate fog, leaving a user with partially restricted vision.
Alternatively, if enough power and current were supplied to the eye-shield 850 in order to dissipate all potential fog across the entire surface of the eye-shield, hot spots would form in the regions around the perimeter of the layered lens 852 where current flows in the shortest, most direct path between upper bus bars 856a, 856c and lower bus bars 858a, 858c, which would use unnecessary and excessive amounts of power from battery 860, lessening the total time a user or wearer could use the eye-shield 850 to dissipate fog. The gaps between upper bus bars 856a, 856b, 856c and lower bus bars 858a, 858b, 858c would help to create a more uniform and customized heating of the eye-shield 850 than would previously described eye-shield 800. Eye-shield 850 would not, however, create an ideal situation to uniformly heat layered lens 852 while still conserving power, though unlike eye-shield 800, some of the failings of eye-shield 850 could be alleviated with a multi-channel power source. Either way, eye-shield 850 might be bulky and cumbersome because it would require multiple positive circuit wires and multiple negative circuit wires, each leading to upper bus bars 856a, 856b, 856c and lower bus bars 858a, 858b, 858c. Adding so many components would also require added expense and time to assemble and may detract from an otherwise desirable sleek design.
Thus, there is needed a bus bar interconnection system which is less labor intensive to manufacture and assemble, and such a system would ideally not require excess wiring or other circuitry.